If he is going behind your back, and talking to ex's then this is a BIG RED FLAG. If this was me I would get rid of him. You need to stand up for yourself and let him know that your not going to tolerate his poor behavior. If he really cares and loves you, he will do what is right. When he screws up don't tell him your sorry. Let him come to you. If you don't put him in his place then he's just going to keep doing what he is doing.